<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>js运算符</title>
</head>
<body>
	<script type="text/javascript">
		/**
		 *  赋值运算符  =   +=   -= 等
			算术运算符  +  -   *   / 等
			字符串的 + 运算符 
		 */

		var a = 1; 
		a += 3;   // a = a + 3;
		console.log(a);

		var b = 2;
		b = b * 3; 
		console.log(b);


		var c = 'hello';
		var d = 'world';
		var e = c + d;
		console.log(e);
	</script>
</body>
</html>